Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Apr. 02, 2016	Apr. 04, 2015
Statement of Cash Flows [Abstract]
Cash and cash equivalents at beginning of period	$ 616,686	$ 932,161
Cash flows from operating activities:
Net income	50,562	36,259
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	31,231	29,433
Amortization of debt discount and fees	255	5,945
Stock-based compensation	24,632	21,861
Gain on investments, net	(2,617)	(1,270)
Deferred income taxes	1,623	1,864
Other non-cash items	209	929
Changes in operating assets and liabilities, net of effect of acquired businesses:
Receivables	11,618	(12,450)
Inventories	(3,714)	1,682
Prepaid expenses and other	(10,132)	(10,004)
Other assets	(3,595)	3,627
Accounts payable and accrued liabilities	(42,557)	(44,754)
Deferred revenue	30,710	16,812
Other long-term liabilities	(5,034)	(3,246)
Net cash provided by operating activities	83,191	46,688
Cash flows from investing activities:
Purchases of available-for-sale securities	(20,525)	(33,161)
Proceeds from the sale of available-for-sale securities	1,000	20,551
Proceeds from the maturity of available-for-sale securities	19,000	10,350
Proceeds from the sale of long-term investments	2,583	1,364
Purchases of property, plant and equipment	(12,116)	(7,520)
Cash paid in business combinations and asset acquisitions, net of cash acquired	(3,853)	0
Net cash used for investing activities	(13,911)	(8,416)
Cash flows from financing activities:
Proceeds from term loans	300,000	0
Proceeds from revolving credit facility	50,000	0
Payment of convertible notes	0	(53,862)
Payment of convertible notes embedded conversion derivative liability	0	(77,139)
Proceeds from convertible notes hedges	0	77,139
Payment of debt issuance costs	(542)	0
Excess tax benefits from stock-based compensation	0	6,482
Proceeds from issuance of common stock	24,200	24,609
Stock received for payment of employee taxes on vesting of restricted stock	(15,225)	(14,114)
Payments for repurchases of common stock	(240,000)	(36,797)
Net cash provided by (used for) financing activities	118,433	(73,682)
Effect of exchange rate changes on cash and cash equivalents	6,001	(9,015)
Increase (decrease) in cash and cash equivalents	193,714	(44,425)
Cash and cash equivalents at end of period	810,400	887,736
Supplemental cash flow information:
Cash paid for interest	109	125
Cash paid for taxes, net	$ 4,799	$ 10,868